OLATOKUN & MAKINDE: CITATION NALYSIS OF DISSERTATIONS 117Annals of Library and Information Studies

Vol. 56, June 2009, pp.117-128

Citation analysis of dissertations submitted to the Department

of Animal Science, University of Ibadan, Nigeria

Wole Michael Olatokun1 and Olayinka Makinde2

1Department of Library and Information Studies, University of Botswana, Gaborone,

Email: woleabbeyolatokun@yahoo.co.uk2Africa Regional Centre for Information Science (ARCIS), University of Ibadan, Nigeria

Citations in master’s degree dissertations submitted to the Department of Animal Science, University of Ibadan, Nigeria

during the period 2000-2007 were analysed for finding possible relationships between citing, cited articles and authors.

Frequency and percentage distributions (presented in charts, tables, and graphs) and measures of central tendency were used to

analyse data. Findings showed that journals were the most utilized reference materials in the dissertations. Also, poultry

nutrition works had the highest number of dissertations followed by agricultural biochemistry and nutrition. The lowest number

of dissertations was from forage production and management and monogastric nutrition with just two dissertations each. The

findings from this study could serve as a user study with implications for both collection development and user services design

in libraries. Future studies could focus on ascertaining the implications of collection of reference materials to project and article

referencing, instruction in classes and outreach.

Introduction

In his essay on citation analysis, King1 pointed out that

scientists are drowning in a flood of information overload.

Remarkably, thousands of scientific studies are published

on a daily basis. One method for tracking and evaluating

research is citation analysis. Citation analysis works

because scientists leave an unmistakable trail behind

them as they report their work- a trail of footnotes.

Today, a scientific publication is easily recognized by its

footnotes, endnotes and references to other scientific

articles or books2. Contributions to scientific knowledge

are often crystallized in the form of a scientific article.

Such contributions may take the form of new facts, new

hypotheses, new theories or theorems, new explanations

or a new synthesis of existing facts3. In each case, a

metamorphosis has taken place from an existing, say

‘old’ situation, to a ‘new’ one. The metamorphosis itself

takes place in the head of the investigators with the

help of scientific equipment and is usually invisible to

outsiders, but scientific tradition requires that an author

refer to earlier articles, which relate to the theme of

his/her paper. The author must clarify his/her starting

point. Identifying those predecessors whose concepts,

methods, discoveries, etc. have inspired or were used

in developing ‘the new things’ that reveal ‘the old

things’. Viewed from another angle, the author

acknowledges a group of inspirational articles written

by earlier researchers by referring to them4.

Citation analysis reflects on citation practices5. Citation

analysis is also seen as that which is used to determine

competitive position of authors, to study the structure of

literature, to manage a collection of journals, to define the

structure of science and for scientists to identify useful

journals among other things6. From an application point

of view, citation analysis may be considered as a

collaborative peer effort to analyze and promote the quality

of scholarly publication and research7. Citation analyses

study the patterns of citations in documents, an objective

method for gathering data about information needs8.

Williams and Fletcher9 explained citation analysis as a non-

intrusive method of finding patterns in a specific

population’s use of research materials. Meho10 has

observed that citation analysis is actually a branch of

information science in which researchers study the way

articles in a scholarly field are accessed and referenced

by others. It has been used for the purpose of scholarly

analysis and evaluation in several fields of human

endeavour. Johnson11 pointed out that citation studies

reveal much about scholarly communication and can be

an effective tool to guide collection development in

academic libraries.

It is against this background that in this study, citation

analysis is employed in studying Masters’ dissertations

submitted to the department of Animal Science, University

of Ibadan, Nigeria (2000-2007) with a view to finding out

citation practices in the dissertations.

118 ANN. LIB. INF. STU., JUNE 2009

The Department of Animal Science, University of Ibadan

was founded in 1967 and is one of the seven departments

under the Faculty of Agriculture and Forestry. In this

study, the terms reference material and cited item are

used interchangeably. The following research questions

guided the study:

• Which citation formats are used mostly in the

dissertations submitted to the department of

animal science?

• Which are the most cited items in the

dissertations and to what extent do citations

apply to Bradford and Zipf laws?

• What is the age of cited items in the

dissertations?

• What are the most frequently cited journals in

animal science?

• What is the trend in the number of citations over

the period 2000 – 2007?

• Which subject areas within animal science areas

of specialization have the highest number of

dissertations?

• To what extent do masters’ students in the

department of animal science use journals from

non-animal science disciplines?

• Are there changing/shifting foci of study area?

If Yes, towards which area?

• To what extent do the dissertations contain

journals from non-animal science disciplines?

• What is the impact of the internet on referencing

in the dissertations over the years?

• How do citations patterns vary among animal

science discipline?

Previous studies

A survey of the literature illustrates the breadth and

potential application of conducting a citation analysis.

Labonte 12 carried out citation analysis to determine if the

science-engineering library at the University of California

at Santa Barbara (UCSB) is meeting the needs of an

interdisciplinary group of 60 faculty members at the new

California Nanosystems Institute. The study was aimed

at developing a core list of journals and identifying journals

Table 1–– Distribution of citations in the dissertations

Materials Journals Books Conference Web Technical Government Theses & Miscellaneous Total

referenced papers resources reports & documents dissertations

standards

Number 6875 2694 1025 (8%) 110 (1%) 224 (2%) 451 (4%) 327 (3%) 668 (5%) 12374

of (55%) (22%) (100%)

reference

and %

Table 2–– Distribution of citations by year

Type of reference materials/year 2000 2001 2002 2003 2004 2005 2006 2007

Journals 931 656 484 1992 1010 482 1200 120

Books 426 247 185 632 359 317 474 54

Conference papers 139 113 62 175 185 100 217 34

Web Resources 0 0 0 9 23 24 52 2

Technical reports & standards 38 18 11 43 28 26 49 1

Government documents 76 76 43 82 61 30 74 9

Theses & dissertations 50 48 22 48 57 36 59 7

Miscellaneous 99 77 21 104 92 77 177 21

Total citations 1759 1235 828 3085 1825 1092 2302 248

Number of dissertations 20 15 6 24 20 13 23 5

OLATOKUN & MAKINDE: CITATION NAL YSIS OF DISSERTATIONS 119

2007

2007

20062005

2004

2003

2002

2001

2000

Average citation rate in the dissertations876 • ... -, - 20055 L .--- - 20044 L.. ~ -30853 ,-----,. ~?~ . 20022 • r 1?':U::: 20011 • ~--- 2000

Fig.l- Total no. of citations for the dissertation Fig.2- Average citation rate in the dissertations

Table 3 - Citations by type and year

Year!Format

Journals Books Conference

papers

Miscellaneous Governmentdocuments

Theses &dissertations

Technical

reports &standards

Web

resourcesTotal

2000 931426139 997650380 1759

2001

656247113 777648180 1235

2002

48418562 214322110 828

2003

1992632175 1048248439 3085

2004

1010357185 9261573823 1825

2005

482317100 7730362624 1092

2006

1200474217 177745949522302

2007

1205434 219712 248

Total

687526941025 66845132722411012374

that should be added to the collections in the sciences­

engineering library at UCSB. Results from the studyindicated that the library subscribed to 98 percent of thejournals in which faculty members are publishing or citingfrequently. The paper suggests that this information isuseful to map the citation patterns of a newinterdisciplinary field and can be used for future collectionmanagement decisions. Williams and Fletcher!3performed a citation analysis on materials used bygraduate students in engineering (comprising theengineering discipline of aerospace, agricultural,electrical, chemical, civil, and computational engineering)at Mississippi State University. The essence of thecitation research was to guide library collectiondevelopment decisions. The case study found thatjournals (38%), conference papers (19%), and books(18%) are the most heavily used formats, with books

aging more slowly than other formats. Core journals listsare developed by total citations and by number of citingauthors. Variations among engineering disciplines wereidentified, including variations in format, age and subjectclassification of journals. The results of this studysuggested three areas in need of future research. First,while journal ranking are usually based on total numberof citations, ranking by number of citing authors may beuseful for studies of masters' dissertations and doctoral

theses. Second, the Library of Congress Classificationofjoumals cited indicates significant variation in subjectclasses cited among engineering disciplines.

The work by Spies14reviewed fourteen "major" journalsof exploration geophysics for "effectiveness". This paperpresented a basic tenet of citation analysis as follows:the references that an author cites are a roughly valid

120 ANN. LIB. INF. STU., JUNE 2009

indicator of influence, hence value, to his work. A measure

of cost effectiveness was also incorporated into this study

as subscription costs and citation rates were compared

between commercial publications and those produced

by professional societies. Uzun, Menard & Ozel15 studied

the citation rates of 572 Turkish physics publications that

appeared in the source journals listed in the Science

Citation Index. This analysis was global in scope as is

commonly the case with citation studies. They examined

impact factor, immediacy index, citation frequency, and

the nationality of the publishing house. The question which

these normal parameters and scope raise for librarians

was how relevant it was to the local collection for which

they had a responsibility to build based upon the research

and curriculum program ongoing at the institution.

Rousseau16 resented a citation distribution of mathematics

journals, wherein it is proposed that a four-year impact

factor would be more suited to mathematics than the

more or less typical two-year impact factor used in

Science Citation Index.

Hurd17 categorized journals in a sample population

according to the disciplines of Physics, Biology,

Chemistry, and Engineering. The categorization was done

according to the Ulrich’s subject classification. The article

also specified the number of citations for the different

formats of materials such as journals, monographs,

conference proceedings, dissertation, unpublished and

others which included government documents,

handbooks, tables, technical reports and software. The

total number of citations was 1931 taken from 57 articles.

Journals formed the largest citations. Redman, Manakyan,

and Tanner18 presented an analysis of the citation patterns

and rankings for journals in real estate and related areas

for the period 1990-1995. Journals were ranked based

on the number of times they were cited in four base

journals with adjustments for journal size and longevity.

The results showed that Real Estate Economics is the

most cited journal among real estate publications followed

closely by the Journal of Real Estate Finance and

Economics and the Journal of Real Estate Research.

A temporal analysis revealed a shift in citations over the

time period, away from the traditional economics and

practitioner-oriented journals to the academic real estate

journals. Chuang19 carried out a study using citation

analysis to identify major themes and contribution to

Health and Insurance literature during the period 1999-

2003. Results showed that the most cited articles were

published in 10 unique journals, only 6 of which were

close to health care.

Muhammad and Khalid20 carried out a citation analysis

of two core Pakistani economic journals. Selected

volumes of the Pakistan Development Review (PDR)

and the Pakistan Economic and Social Review (PESR)

were analysed to find the citation patterns of their articles.

Eight volumes of each journal were selected, two volumes

representing a decade. The results reveal that the PDR

has been the most cited journal. More than 50 per cent

of the citations from both journals were single-authored.

More than 50 per cent of the citations were from non-

journal sources, mainly books. Although citations from

online sources were seen, it was a negligible number.

Georgas and Cullars21 made a citation study of the

characteristics of the Linguistic literature of which

citations were obtained from the Language and

Linguistics Behavior Abstracts (LLBA) database. They

specified the number and percentage of citations in terms

of type of source cited such as monographs, articles in

books, journal articles and theses. The result showed

that the journals articles had the highest score in the cited

and citing sources which were 73.3% and 42.8%.

Wohlin22 analysed the most cited articles in software

engineering journals. The article specified that citation

Table 4 –– Age of materials

Age of oldest 50% of items 80% of items 10 years old 5 years old or

item (years) less than (years) Less than or less (%) Less (%)

(years)

All formats 79 8 14 62 56

Books 65 10 20 54 51

Conference 38 7 14 72 71

Journals 79 9 17 61 59

OLATOKUN & MAKINDE: CITATION NALYSIS OF DISSERTATIONS 121

and related work provided a crucial resource to research

work. The author also conducted an analysis using the

ISI Web of Science to identify the most cited software

engineering journal articles published in 1999 with the

objective being to identify and list articles that have

influenced other than the most which was measured in

the citation count. The articles were most cited by others.

A list of 20 most cited articles was presented from his

results.

Data collection and analysis

The research design adopted was a descriptive study.

Two major sources of data used were dissertations

submitted for master’s degree in the department of

Animal Science, University of Ibadan, Nigeria covering

the period 2000-2007 and the database of dissertations

in the department. The sampling procedure for the study

was purposive since data was being collected specifying

a target period 2000-2007. This sample also represented

the total population of the dissertations. In all, 126 masters’

dissertations were analysed.

Each dissertation was manually examined and citations

were extracted from the references section of each of

the dissertation. The method of data collection was

document extraction through content analyses. Data

extracted from the dissertations included year of

publication (year of project submission), year of cited

work, year of the oldest materials cited, number of

citations, most cited year (mode of occurrence), title of

project work, volume of project work, type of cited

journal, journal type cited and years cited. The citations

in each cited title were broken into eight categories

namely: journals (serials other than monographic series

and conference proceedings), books, conference papers,

web resources and technical reports and standards

(including government technical reports). Others were

government documents (state, federal and foreign),

theses and dissertations and miscellaneous material

(patents, personal communications, product literature,

software and software manuals, university extension

documents, unpublished materials, and others).

The data extracted were entered into MS-Excel

worksheet. Frequency distributions charts, graphs, and

measures of central tendency like mean, mode and median

were obtained using the MS-Excel.

Results

Distribution of citations in the dissertations

The citations in the dissertations totaled 12,374. The

results were presented in Tables 1& 2 and Figures

1 & 2. Table 1 showed the distribution of types of

Table 5 –– Top twenty core journals cited in the Masters’ dissertations

Rank Journal Number of citations

1 Poultry Science 926

2 Animal Feed Science and Technology 707

3 Journal of Nutrition 413

4 Journal of Animal Science 299

5 Journal of Animal Production 266

6 Journal of Agriculture and Food Chemistry 197

7 Journal of Animal Physiology and Animal Nutrition 164

8 Journal of Agricultural Science 133

9 British Poultry Science 109

10 Journal of Science, Food and Agriculture 86

11 Nigerian Journal of Animal Production 68

12 Biochemistry Journal 67

13 British Veterinary Journal 65

14 World Poultry Science Journal 55

15 British Journal of Nutrition 50

16 Journal of Animal Nutrition 40

17 Tropical Animal Production Investigation 38

18 Livestock Production Science 38

19 International Journal of Goat and Sheep Research 37

20 Development in Animal and Veterinary Science 37

122 ANN. LIB. INF. STU., JUNE 2009

reference materials cited in the dissertations as grouped

or categorized in this study, Figures 1 and 2 shows the

total of all citations by year.

From the results presented in Table 1, it can be observed

that citations to journals alone accounted for more than

half of the total citations constituting 55%. This was

followed by citations to books that were 22%. The

descending order of other materials cited was as follows:

conference papers (8%), miscellaneous (5%),

government document (4%), theses and dissertations

(3%), technical reports and standards (2%) and web

resources (1%). There was an average of 98 citations

per dissertation for the 126 available masters’

dissertations. Previous studies that have ranked reference

materials corroborate that journals were the most cited

reference material, with other citation formats having

varying percentages in their rankings and they may vary

widely23-29.

As shown in Figure 1, the highest number of citations

for dissertations was recorded in 2003 followed by 2006

with the least recorded in the year 2007.

As presented in Figure 2, 2007 had the highest citations

while 2000 recorded the least. The distribution of citations

to the dissertations was unsymmetrical or skewed.

From Table 2, it can be observed that journals had highest

values through all the years among the reference materials

cited in the dissertations. The highest citation to journals

was 1992 in 2003. However, web resources were the

least cited.

Distribution of citations by type of reference materials

Cited reference materials were grouped into eight

categories as follows: journals (serials other than

monographic series and conference proceedings), books,

conference papers, web resources, technical reports and

standards (including government technical reports),

government documents (state, federal and foreign),

theses and dissertations, and miscellaneous documents

sersonal communications, product literature, software and

software manuals, university extension documents,

unpublished materials and others).

Analysis revealed that the highest overall citation to

journals was recorded in the year 2003 with 1992 citations

followed by 1200 citations in 2004. The least number of

citations was 120 in 2007. Table 3 also shows that the

highest overall citation to books was recorded in the year

2003 with 632 citations followed by 474 citations in the

year 2006 with the least being 54 citations in 2007. For

that of conference papers, the highest overall citation

was recorded in the year 2006 with 217 citations followed

by 185 citations in year 2004. The least was 34 citations

in 2007. Web resources recorded 52 citations as the

highest overall citations in the year 2006 followed by 24

citations in year 2005. However zero citations were

recorded in years 2000, 2001, and 2003. The highest

citation to technical reports and standards varied from

that of the web by three counts having a value of 49

citations in the year 2006 followed by 43 citations in year

2003. The least was one citation in 2007. Government

documents had the highest overall citation in the year

2003 with 82 citations and closely followed by 76 citations

occurring twice in years 2000 and 2001. The least was 9

citations in 2007. The uppermost overall citation to theses

and dissertations was evidenced in the year 2006 with

59 citations followed by 57 citations in year 2004. The

least was 7 citations in 2007. The topmost overall citations

to miscellaneous documents were also indicated in the

year 2006 with 177 citations followed by 104 citations in

year 2003. The least was 21 citations occurring in years

2002 and 2007 (Table 3).

As displayed in Table 3, journals and books were the

most cited materials over the years with journals being

cited as the foremost cited reference materials all through

the years 2000-2007. Conference materials, government

documents, technical reports and standards and web

resources also followed in this order with web resources

being the least cited.

Age of citations

Age is the length of time a reference material has existed

and it is usually measured in years. However in this study,

percentages were used to describe reference materials

(items) to make them more expressive in years. The

results on the age of citations are presented in Table 4.

The oldest reference material in the dissertations was a

1921 serial material (journal) named Chemistry Abstract.

Two earlier studies have found that majority of reference

materials cited in the citation analysis studies they carried

out were less than eight years old30,31. In this study, 50%

of all reference materials cited in the dissertations was

less than eight years old and 80% within the last 14 years.

Conference papers were the most recent materials with

72% published in the last 10 years. Journal was thus the

oldest reference material cited. Therefore, conference

OLATOKUN & MAKINDE: CITATION NALYSIS OF DISSERTATIONS 123

papers tended to be more current than books or journals.

This is in agreement with Williams & Fletcher32 that noted

that 76% of conference papers were also published in

the last 10 years in their citation analysis study. Also,

close to half of books were less than 5 years old (49%)

while 55% of conference papers and 52% of journals fit

that category.

Journals citations distribution

In all, eight-hundred and one journal titles were found in

the dissertations. Table 5 shows the frequency of

occurrence of journals cited in the field of animal science

as found in the dissertations.

Poultry Science Journal (PSJ) was the most cited

journal having a total of 926 citations. This was found in

78 dissertations. The probability of finding a dissertation

that cited PSJ article is 0.6190 indicating high dissertation

citations and the visibility of PSJ in the dissertations. The

highest citation by any individual to PSJ was 36 and this

occurred in 2004.

Citations to Animal Feed, Science and Technology

Journal (AFSTJ) ranked as second on the list of most

cited journals having 707 citations. This was found in 69

dissertations. The probability of finding a dissertation that

cited AFSTJ is 0.5476. The highest citation by any

individual to AFSTJ was 29 and this occurred in 2004.

Journal of Nutrition (JON) ranked third in the list of

most cited journals having a total of 413 citations. This

was found in 43 dissertations. Therefore the probability

of finding a dissertation that cited JON article is 0.3412.

The highest citation by any individual to JON is 20 and

this occurred in 2003.

Among the top twenty journals used for analysis, the

least cited journal were Tropical Animal Production

Investigation and Livestock Production Science with 38

citations each, and International Journal of Goat and

Sheep Research and Development in Animal and

Veterinary Science with 37 citations each.

Study areas in the dissertations

The results of the analyses performed to find out the

distribution of the dissertations in the sub-fields of animalscience are presented in Table 6.

Table 6 shows that poultry nutrition is the subfield that is

mostly researched between years 2000-2007 with 27

dissertations (21%). This was followed by agricultural

biochemistry and nutrition with 25 dissertations (19.8%).

The least researched subfields were forage production

and management and monogastric nutrition that were

the study areas of 2 dissertations each. Poultry nutrition

peaked in 2000 with eleven masters’ dissertations

focusing on the subfield.

Citation pattern among animal science disciplines

Journals were the most cited reference material for the

different animal science disciplines between years 2000-

2007. This was followed by books. Table 7 shows

citations for the coverage period. It was only in forage

production and management that books were most cited.

Web resources were the least cited as it was not cited at

all in any of the dissertations of forage production and

management. However, it ranked sixth in the animal

physiology subfield with 41 citations, being cited more

than theses and dissertations (30 citations) and technical

reports and standards (26 citations).

Discussion

Citations formats

The citation formats used in the dissertations include

journals, books, conference papers, web resources,

technical reports and standards (including government

technical reports) and government documents (comprising

state, federal and foreign government documents). Other

citation formats used were theses and dissertations and

miscellaneous reference materials (comprising patents,

personal communication, product literature, software and

software manuals, university extension documents,

unpublished materials, and others). This classification

of citation formats is in line with the formats that have

been extensively used in various works on citation

analysis. Among them were Williams & Fletcher33 who

divided the reference materials (formats) of their citation

study into eight groups. Actually, this study strongly builds

on Williams and Fletcher’s citation analysis to relate it to

the animal science discipline. Johnson34 and Gooden35

also carried out citation studies in which five groups were

clearly identified. This study improved on and added to

these groups since animal science as an agricultural

discipline utilizes myriads of reference materials.

Most cited items, Bradford and Zipf laws?

The most cited items were journals which accounted for

more than half of the total citations 6875 (55%). The

124 ANN. LIB. INF. STU., JUNE 2009

use of web resources was very low 1%, (10 citations) in

the dissertations. Other reference materials or citation

formats apart from books and conference papers that

ranked 2nd and 3 rd were moderately used in the

dissertations. Many citation analyses buttress the claim

in this study that journals are the most used materials in

any research field judging from the fact that they point

to currency of research works36-48. It is also in support

of Johnson49 where journals ranked 1st and books ranked

2nd as well as that of studies like Dombrowski50.

In addition, Bradford’s Law of Scatter51 also applies in

this study with 12 journals accounting for half of the

journal citations in the field of animal science. This kind

of user-data implications should be considered in

evaluating journals. Therefore, the Bradford’s zone of

Table 6 –– Study areas in the dissertations

Field/Year 2000 2001 2002 2003 2004 2005 2006 2007 Total

Animal Breeding & Genetics 0 0 0 3 3 2 2 1 11

Monogastric Nutrition 1 1 0 0 0 0 0 0 2

Agricultural Biochemistry & Nutrition 1 7 0 4 3 4 6 0 25

Animal Products & Meat Science 1 0 0 0 1 1 2 1 6

Animal Production 2 2 0 6 6 2 4 1 23

Ruminant Nutrition 3 3 1 2 2 1 2 0 14

Animal Physiology 1 0 1 3 4 2 4 1 16

Poultry Nutrition 11 2 2 6 1 1 3 1 27

Forage Production & Management 0 0 2 0 0 0 0 0 2

Total 20 15 6 24 20 13 23 5 126

Table 7 –– Citation pattern among animal science disciplines in the dissertations

Field/Format Journals Books Conference Web Technical Government Theses Misc.

Papers Resources Reports & Documents &

Standards Dissert

Animal Breeding & Genetics 368 122 121 20 5 35 31 53

Monogastric Nutrition 74 18 12 0 1 20 5 19

Agricultural Biochemistry & 1508 608 171 28 42 97 62 128

Nutrition

Animal Products & Meat 327 112 34 7 8 8 17 41

Science

Animal Production 1432 429 165 7 51 72 69 106

Ruminant Nutrition 773 362 188 4 41 75 50 98

Animal Physiology 926 442 84 41 26 44 30 99

Poultry Nutrition 1382 489 214 3 44 86 59 112

Forage Production & 85 90 26 0 6 14 4 8

Management

few journals accounting for many citations is confirmed

by the findings from this study. In one of the early citation

studies, Gross and Gross52 discovered that very few

journals were cited frequently in the Journal of the

American Chemical Society, while many journals were

only cited once. Their findings concur with Zipf’s law,

which states that while few items occur often, many

items occur rarely53.

Age of the cited items

The oldest cited item was a periodical. Fifty percent of

all reference materials cited in the dissertations was less

than eight years old. Conference materials were the most

recent materials with 72% dissertations published in the

last 10 years. Eighty percent of books were less than 20

years. This supports Musser & Conkling’s54

OLATOKUN & MAKINDE: CITATION NALYSIS OF DISSERTATIONS 125

recommendation that books should not be placed in

storage as quickly as other citation formats because of a

lasting referral to them. Johnson 55 observed that age of

cited works was much less diverse but in this study age

of reference materials were much more diverse. This

agrees with Williams & Fletcher 56 that much diversity

was experienced in ages of materials used in their study.

Most frequently cited journals

The most cited journals in the dissertations were Poultry

Science Journal (926 citations) followed by Animal

Feed Science and Technology Journal (707 citations),

Journal of Nutrition (413 citations), and Journal of

Animal Science (266 citations). The least cited journal

titles include Phytochemistry, Cancer and

Milchwissenshaft which were only cited once. The most

frequently cited journals were actually agricultural

journals which is in line with the facts that any research

discipline tend to cite more from the journals that are

from core areas of that discipline57-61.

Average number of citations per dissertation

A total of 12, 374 reference materials were cited in 126

dissertations. This gives an average of 98 citations per

dissertation. This is in agreement with Gooden62 where

citation analysis of the Ohio State University chemistry

department had their number of citations ranging from a

low of 24 to a high of 491 and averaged about 123

citations each. Therefore, the number of citations in this

study is a good indicator of a relatively good citation

pattern in terms of number of materials cited in the animal

science bibliographies.

Trend in number of citations

The number of citations to journals in the dissertations

tended to be highest for every year of the coverage period

of this study. This is definitely responsible for journals

being ranked as the topmost cited material while number

of citations to web resources tended to be lowest for

every year of the coverage period of this study. Values

for citations were seen to be constantly changing for all

reference materials experiencing lows and highs at

different years. However, visible highs were glaring in

journals, books and conference papers in the

dissertations. Number of citations to web resources

experienced highs in 2006 (52 citations). This study is in

agreement with the studies of Aina63 and Williams &

Fletcher64 where journals among all reference materials

ranked highest throughout all the years of the coverage

period of their citation analyses.

Subject areas of specialization

Poultry nutrition works had the highest number of

occurrences (27 dissertations, 21%), followed by

agricultural biochemistry and nutrition (25 dissertations,

19.8%). The areas of specialization with lowest number

of dissertations were forage production and management

and monogastric nutrition with two dissertations each.

Williams & Fletcher 65pointed out that computational

engineering had the highest number of dissertation

submission. Also, the old areas, poultry science and

animal biochemistry and nutrition in this study had the

highest number of theses submission.

Changing/shifting foci of study area

In the dissertations, poultry nutrition is an area that is

dwindling greatly having reached its peak in 2000. Also,

studies in ruminant nutrition diminished as well with zero

studies from year 2002 to 2007. Animal biochemistry

and nutrition studies despite being ranked second in terms

of dissertation submission dwindled experiencing visible

highs and lows with zero dissertation work for year 2007.

Animal physiology can be weakly considered to be the

new focus of the masters students as the number of

dissertations increased over time but gradually recorded

just one study in 2007. Citation analysis for different fields

have shown that there would always be changing or

shifting focus of study area because of student discretion,

faculty area of specialization, available dissertation

supervisors and funding66-67.

Citations of works from non-animal science disciplines

Animal science as an agricultural science discipline is

an area that extensively makes use of a wide range of

science journals ranging from medical sciences, life

sciences, mathematics, engineering (especially

agricultural engineering), food sciences, veterinary

sciences and even social sciences. Close to 20% of the

journals identified in this study were found to be core

animal science journals. The remaining 80% ranged

among the other sciences including few additions from

other areas of study apart from the sciences. Thus, it

can be said that animal science uses more journals that

are not core animal science journals. However, this study

reveals that the core animal science journals account

for the bulk of the citations in the discipline’s

bibliographies. This is in line with the work of Garfield68

where he clearly put forth that agricultural scientists use

and cite the same frequently cited basic research journals

used by all other research workers in life sciences. This

was Garfield’s argument when he stated emphatically

126 ANN. LIB. INF. STU., JUNE 2009

that an agricultural citation index is embedded in science

citation index. This study shows that about 80% of the

total journals used in postgraduate studies in animal

science are actually from the basic sciences.

Impact of the Internet

Although the Internet was least used in all the cited

reference materials, nevertheless the use of web

resources in animal science research as seen in the

dissertations is on the rise. Though in the dissertations,

internet sources were not cited in the first three years

(2000-2003) it however greatly increased in the last 4

years especially achieving a peak of 52 cited references,

although its utilization fell sharply to two cited items in

2007. This finding supports Aina’s69observation that the

web was the least source used. However, Williams &

Fletcher70 had a contrary result in their study of master

in engineering students. The web was ranked 4th behind

journals, conference papers and books in eight-group

classification of reference materials used in engineering.

Web usage from various citation analyses carried out

might simply indicate that its thorough utilization would

be discipline independent and would also anchor on the

promotion of information technologies especially the

internet by institutions and governments.

Variations in citation patterns

In the dissertations, all animal science sub-disciplines cite

journals extensively. However, animal nutrition and

biochemistry cited journal reference materials from other

disciplines. Animal production was ranked second in

terms of dissertation submission but was rated eighth in

citation to journals. Zero web citations were recorded

for monogastric nutrition and forage production and

management. Other reference materials displayed a

reasonable level of variability in their citation patterns.

These variations concured with Williams & Fletcher71

and Aina72 who indicated that different sub-fields of a

discipline utilize varying degrees of reference materials

pointing to their varying citation patterns and this might

also be discipline specific.

Conclusions

Citation analysis should be used at institutional and

governmental levels for the formulation of citation-based

science policy for an all round development in science

and agriculture. The findings from this study also show

several important areas of reference materials as vital

information sources in research for postgraduate

students. This will no doubt help the University of Ibadan’s

main library and other departmental libraries in their

budget planning to judiciously use their shrinking budgets

and funds to make far-reaching library-material collection

decisions.

Although, several findings were pointed out in this study

but a single research cannot be all-encompassing to point

out the multifarious existing problems that call for urgent

solutions. With this study carried out in a single university,

it would be beneficial to replicate it in some of the other

top ten universities with virile animal science departments

in order to compare the results. This will help in

answering questions like: Are the core materials similar?

Are other sources mentioned in this study apart from the

journal also beneficial to their research works? These

answers could prove to be helpful to already established

university libraries and new private universities seeking

to establish animal science departments with implications

for boosting existing and new collections.

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